/*******************************************************************************
 * Copyright (c) 2009-2011 Luaj.org. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 ******************************************************************************/
package org.luaj.vm2;

/**
 * Extension of {@link LuaValue} which can hold a Java boolean as its value.
 * <p>
 * These instance are not instantiated directly by clients.
 * Instead, there are exactly twon instances of this class,
 * {@link LuaValue#TRUE} and {@link LuaValue#FALSE}
 * representing the lua values {@code true} and {@link false}.
 * The function {@link LuaValue#valueOf(boolean)} will always
 * return one of these two values.
 * <p>
 * Any {@link LuaValue} can be converted to its equivalent
 * boolean representation using {@link LuaValue#toboolean()}
 * <p>
 *
 * @see LuaValue
 * @see LuaValue#valueOf(boolean)
 * @see LuaValue#TRUE
 * @see LuaValue#FALSE
 */
public final class LuaBoolean extends LuaValue {

    /**
     * The singleton instance representing lua {@code true}
     */
    static LuaBoolean _TRUE = new LuaBoolean(true);

    /**
     * The singleton instance representing lua {@code false}
     */
    static LuaBoolean _FALSE = new LuaBoolean(false);

    /**
     * Shared static metatable for boolean values represented in lua.
     */
    public static LuaValue s_metatable;

    /**
     * The value of the boolean
     */
    public boolean v;

    LuaBoolean(boolean b) {
        this.v = b;
    }

    public int type() {
        return LuaValue.TBOOLEAN;
    }

    public String typename() {
        return "boolean";
    }

    public boolean isboolean() {
        return true;
    }

    public LuaValue not() {
        return v ? FALSE : LuaValue.TRUE;
    }

    /**
     * Return the boolean value for this boolean
     *
     * @return value as a Java boolean
     */
//	public boolean booleanValue() {
//		return v;
//	}
    public boolean toboolean() {
        return v;
    }

    public String tojstring() {
        return v ? "true" : "false";
    }

    public boolean optboolean(boolean defval) {
        return this.v;
    }

    public boolean checkboolean() {
        return v;
    }

    public LuaValue getmetatable() {
        return s_metatable;
    }
}
